UnTransform.cl File Reference

Euler-XYZ based untransformation script. More...

#include "resources/Scripts/types/types.h"

Include dependency graph for UnTransform.cl:

Functions
__kernel void	entry (const __global uint *iset, const __global int *imove, __global vec *r, __global vec *normal, __global vec *tangent, unsigned int N, unsigned int motion_iset, vec motion_r_in, vec4 motion_a_in)
	Untransform the previously applied EulerXYZ motion.

Detailed Description

Euler-XYZ based untransformation script.

Function Documentation

entry()

__kernel void entry	(	const __global uint *	iset,
		const __global int *	imove,
		__global vec *	r,
		__global vec *	normal,
		__global vec *	tangent,
		unsigned int	N,
		unsigned int	motion_iset,
		vec	motion_r_in,
		vec4	motion_a_in
	)

Untransform the previously applied EulerXYZ motion.

Just the position and the normal of the particle are modified, but not the velocity which is changed by MotionVelocity.cl.

In EulerXYZ the following transformation is applied to a particle \( a \):

\[ R_z \cdot R_y \cdot R_x \cdot \mathbf{x_a} + \mathbf{cor}, \]

where \( \mathbf{cor} \) is the position of the center of rotation (global translations), and \( R_x, R_y, R_z \) are the rotation matrices:

\[ R_x = \left[ \begin{matrix} 1 & 0 & 0 \\ 0 & \mathrm{cos}(\phi) & -\mathrm{sin}(\phi) \\ 0 & \mathrm{sin}(\phi) & \mathrm{cos}(\phi) \\ \end{matrix} \right], \]

\[ R_y = \left[ \begin{matrix} \mathrm{cos}(\theta) & 0 & \mathrm{sin}(\theta) \\ 0 & 1 & 0 \\ -\mathrm{sin}(\theta) & 0 & \mathrm{cos}(\theta) \\ \end{matrix} \right], \]

\[ R_z = \left[ \begin{matrix} \mathrm{cos}(\psi) & -\mathrm{sin}(\psi) & 0 \\ \mathrm{sin}(\psi) & \mathrm{cos}(\psi) & 0 \\ 0 & 0 & 1 \\ \end{matrix} \right]. \]

Therefore to invert the transformation the following expression can be applied:

\[ R_x^{-1} \cdot R_y^{-1} \cdot R_z^{-1} \cdot \left(\mathbf{x_a} - \mathbf{cor}\right), \]

where the inverse rotation matrices are obtained just using \( -\phi, -\theta, -\psi \) angles.

Parameters

iset	Set of particles index.
imove	Moving flags. imove > 0 for regular fluid particles. imove = 0 for sensors. imove < 0 for boundary elements/particles.
r	Position \( \mathbf{r} \).
normal	Normal \( \mathbf{n} \).
N	Number of particles.
motion_iset	Set of particles affected.
motion_r_in	Center of rotation.
motion_a_in	Rotation angles \( \phi, \theta, \psi \).

See also

MotionTransform.cl